I tried both Aptana Studio (both standalone and Eclipse version) and Netbeans. For my personal taste and needs, I chose Netbeans as my primary IDE.
I think there is no "THE" IDE ideal. Both are very good IDEs, among many others. Try both Aptana and Netbeans so you can see which one is best for YOUR needs!
By the way, one plugin I can't live with is Zen Coding (for Netbeans, Eclipse / Aptana + others): http://code.google.com/p/zen-coding/
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